Assessment of the Modified Prill leg Check and Prill Push Test as Indicators of Vertebral Subluxation by Comparison with Established Indicators

Alan Hartley, PhD
Perry Rush, DC
John Zhang, MD, PhD

The primary objective of this study is to evaluate the potential of the Modified Prill leg check and the Prill Push test as legitimate indicators of subluxation by comparison with other established chiropractic criteria. The modified Prill leg check is reported to indicate the approximate segmental level of a potential upper cervical subluxation. To assess the accuracy of this procedure, we will examine the association between Prill leg check findings and actual misalignments viewed on Blair X-ray spinographs. The data pool for this comparison already exists so this part of the study will be completed within the next few months. We will assess this claim by comparing cervical listings derived using a multicomponent analysis package (The Sherman Package) with those derived using the Prill Push test.

In the second phase of the study we will begin the process of elucidating the mechanisms by which the two Prill tests exert their effects on leg length inequality (LLI). A working hypothesis is presented that describes how push tests may effect LLI in subluxated and nonsubluxated vertebrae. The assumptions intrinsic to this hypothesis will be tested using surface EMG scans of postural muscles during Push tests on subluxated and nonsubluxated vertebrae. The long-term objective of this study is to develop an exhaustive understanding of the physiology responsible for the Prill tests and LLI so that they may be used as reliable chiropractic tools for research and the location and analysis of vertebral subluxation.